Iron is an essential nutrient best known for its role as a component of hemoglobin, the oxygen-carrying protein in the blood. Unfortunately, iron deficiency is surprisingly common.
Iron bioavailability is an important feature of both diet and supplements. This article explodes some common myths about iron and provides guidance on methods of iron supplementation.
Iron deficiency versus anemia
A state of low iron stores, iron deficiency is commonly detected by measuring blood ferritin levels. Although there is some variability in what is considered a “normal” value, many practitioners consider values between 12 to 300 μg/L for men and 12 to 150 μg/L for women as within a normal range.
Iron deficiency is a common cause of
- shortness of breath
- poor immunity and frequent infection
- fragility of hair and nails
- hair loss
- poor growth
Iron deficiency anemia (IDA) is a state of iron deficiency plus low red blood cell, or hemoglobin, counts (under 120 g/L in women, or under 30 g/L in men). Individuals with chronic heart disease and kidney disease have higher rates of IDA.
Who’s at risk of iron deficiency?
- women of reproductive age (due to menstrual blood losses)
- pregnant women
- children (increased demands with growth)
- the elderly (poor intake)
- those with digestive conditions such as celiac or inflammatory bowel disease (IBD) that may reduce intestinal absorption
- vegetarians and vegans
Why vegetarians and vegans?
Although vegetarians consume higher amounts of dietary iron compared to omnivores, because it’s in a nonheme iron form (versus heme iron from meat, fish, and poultry), its bioavailability, or absorption by the body, is much lower.
As a comparison, studies show that heme iron is better absorbed (about 15 to 40 percent) compared to nonheme iron (about 1 to 15 percent).
Roughly 10 to 12 percent of iron in an omnivore diet is in the heme form, while there is zero heme iron in a vegetarian diet.
What about iron supplements
Not all iron supplements are the same. Heme iron supplements show the highest absorption. A study involving patients with iron deficiency anemia showed that oral heme iron supplementation was equal in effectiveness to intravenous iron.
Iron bisglycinate has been shown to raise hemoglobin and ferritin levels as well as ferrous sulphate, and may be better tolerated.
Can you have too much iron?
Although iron is an essential nutrient that is required for normal body function, excess iron can damage the liver, heart, pancreas, and other organs. It’s critical to supplement with iron only if you’ve had your iron status evaluated through appropriate blood tests, and your iron has been shown to be low.